It turns out that Kardashian and Duchesnay, as a result of their partnership, fell afoul of strict FDA rules regarding what companies can and cannot say about prescription drugs via social media. Namely, she did not make mandatory statements about the drug’s side effects and comply with the same rules that require spoken disclaimers at the close of television commercials for prescription drugs.

Kardashian became something of a case study, since her paid endorsements are often published to her personal Instagram account. In this case, the reality show star was in violation of the FDA’s rules because she was posting about the drug as part of a paid partnership. But even otherwise, Kardashian is a social media powerhouse: If she were to promote a drug without being paid to do so, millions of people would still see the post due to her sheer reach. Would the FDA have the right to police posts like that if they’re by influential figures on social media?

The advent of social media platforms–particularly those with character limits, like Twitter–being used for advertising purposes has raised a slew of issues. Despite the potential moneymaking opportunity, companies have shied away from posting ads to social media rather than risk drawing the ire of the FDA; the agency has stringent rules and stiff penalties for non-compliance.

Update: This article has been updated to make clear that the warning letter was sent to Duchesnay and not to Kardashian. In an email, an FDA press officer explained that “While the FDA doesn’t typically comment on the details of a specific compliance action, we understand that the recent social media posts from Kim Kardashian West, which were sponsored by Duchesnay, Inc., may have created some confusion about the FDA’s regulation of prescription drug promotion and recent draft guidances regarding social media. Ultimately, the mission of the FDA’s Office of Prescription Drug Promotion is to protect the public health by ensuring that promotion of approved prescription drugs is truthful, non-misleading and balanced, regardless of the platform used. Our draft guidances for social media recommend that communications on these platforms should present both benefit and risk information so that patients, with their healthcare providers, can make informed decisions about their health.

The FDA issued a Warning Letter to Duchesnay on August 7, 2015, stating that the social media posts issued by Ms. Kardashian West, who was acting as a spokesperson for Diclegis (as she disclosed in her posts and was confirmed by the company), were misleading because they presented efficacy claims and omitted the risks associated with the product, suggesting that the drug is safer than has been demonstrated. The FDA’s action was appropriate and consistent with how we regulate prescription drug promotion across all channels, based on our statutes and regulations, in order to help ensure that patients and their healthcare providers have accurate information about prescription drug products, including both risks and benefits.

Since then, the company has responded to the FDA warning letter by removing the misleading social media posts, and, on Sunday, 8/30, issuing corrective communications on the same channels to inform the public about the potential risks associated with Diclegis.”